remove space to restart game, refactor code slightly

index.html

@@ -22,7 +22,7 @@
         <div class="best-container">0</div>
       </div>
     </div>
-    <p class="game-intro">Join the numbers and get to the <strong>2048 tile!</strong></p>
+    <p class="game-intro">Join the numbers and get the <strong>2048 tile!</strong></p>
     <a class="restart-button">New Game</a>
     <div class="game-container">
       <div class="game-message">

js/keyboard_input_manager.js

@@ -39,16 +39,17 @@ KeyboardInputManager.prototype.listen = function () {
     39: 1, // Right
     40: 2, // Down
     37: 3, // Left
-    75: 0, // vim keybindings
-    76: 1,
-    74: 2,
-    72: 3,
+    75: 0, // Vim up
+    76: 1, // Vim right
+    74: 2, // Vim down
+    72: 3, // Vim left
     87: 0, // W
     68: 1, // D
     83: 2, // S
     65: 3  // A
   };
 
+  // Respond to direction keys
   document.addEventListener("keydown", function (event) {
     var modifiers = event.altKey || event.ctrlKey || event.metaKey ||
                     event.shiftKey;
@@ -59,38 +60,32 @@ KeyboardInputManager.prototype.listen = function () {
         event.preventDefault();
         self.emit("move", mapped);
       }
-
-      if (event.which === 32) self.restart.bind(self)(event);
     }
   });
 
-  var retry = document.querySelector(".retry-button");
-  retry.addEventListener("click", this.restart.bind(this));
-  retry.addEventListener(this.eventTouchend, this.restart.bind(this));
-
-  var restart = document.querySelector(".restart-button");
-  restart.addEventListener("click", this.restart.bind(this));
-  restart.addEventListener("touchend", this.restart.bind(this));
-
-  var keepPlaying = document.querySelector(".keep-playing-button");
-  keepPlaying.addEventListener("click", this.keepPlaying.bind(this));
-  keepPlaying.addEventListener("touchend", this.keepPlaying.bind(this));
+  // Respond to button presses
+  this.bindButtonPress(".retry-button", this.restart);
+  this.bindButtonPress(".restart-button", this.restart);
+  this.bindButtonPress(".keep-playing-button", this.keepPlaying);
 
-  // Listen to swipe events
+  // Respond to swipe events
   var touchStartClientX, touchStartClientY;
   var gameContainer = document.getElementsByClassName("game-container")[0];
 
   gameContainer.addEventListener(this.eventTouchstart, function (event) {
-    if (( !window.navigator.msPointerEnabled && event.touches.length > 1) || event.targetTouches > 1) return;
-    
-    if(window.navigator.msPointerEnabled){
-        touchStartClientX = event.pageX;
-        touchStartClientY = event.pageY;
+    if ((!window.navigator.msPointerEnabled && event.touches.length > 1) ||
+        event.targetTouches > 1) {
+      return; // Ignore if touching with more than 1 finger
+    }
+
+    if (window.navigator.msPointerEnabled) {
+      touchStartClientX = event.pageX;
+      touchStartClientY = event.pageY;
     } else {
-        touchStartClientX = event.touches[0].clientX;
-        touchStartClientY = event.touches[0].clientY;
+      touchStartClientX = event.touches[0].clientX;
+      touchStartClientY = event.touches[0].clientY;
     }
-    
+
     event.preventDefault();
   });
 
@@ -99,15 +94,19 @@ KeyboardInputManager.prototype.listen = function () {
   });
 
   gameContainer.addEventListener(this.eventTouchend, function (event) {
-    if (( !window.navigator.msPointerEnabled && event.touches.length > 0) || event.targetTouches > 0) return;
+    if ((!window.navigator.msPointerEnabled && event.touches.length > 0) ||
+        event.targetTouches > 0) {
+      return; // Ignore if still touching with one or more fingers
+    }
 
     var touchEndClientX, touchEndClientY;
-    if(window.navigator.msPointerEnabled){
-        touchEndClientX = event.pageX;
-        touchEndClientY = event.pageY;
+
+    if (window.navigator.msPointerEnabled) {
+      touchEndClientX = event.pageX;
+      touchEndClientY = event.pageY;
     } else {
-        touchEndClientX = event.changedTouches[0].clientX;
-        touchEndClientY = event.changedTouches[0].clientY;
+      touchEndClientX = event.changedTouches[0].clientX;
+      touchEndClientY = event.changedTouches[0].clientY;
     }
 
     var dx = touchEndClientX - touchStartClientX;
@@ -132,3 +131,9 @@ KeyboardInputManager.prototype.keepPlaying = function (event) {
   event.preventDefault();
   this.emit("keepPlaying");
 };
+
+KeyboardInputManager.prototype.bindButtonPress = function (selector, fn) {
+  var button = document.querySelector(selector);
+  button.addEventListener("click", fn.bind(this));
+  button.addEventListener(this.eventTouchend, fn.bind(this));
+};